The invention relates generally to electrical contacts, and more particularly, to elastomeric electrical contacts.
Interconnect devices are sometimes used to provide electrical connection between different electrical components, such as, but not limited to, integrated circuits and printed circuit boards, for example when removal, replacement, and/or testing of the electrical components is desired. Many of these electrical components have electrical contacts arranged in a “land grid array” (LGA) which is a two-dimensional array of contact pads. One type of interconnect device, known as an “interposer”, has an array of compressible contacts which is placed between the two opposing arrays of the electrical components to provide an electrical connection between the electrical contacts of the opposing arrays.
Establishing reliable contact between the electrical contacts of the opposing electrical component arrays and the electrical contacts of the interposer may sometimes be difficult due to, for example, height variations between electrical contacts of the opposing electrical component arrays and/or the electrical contacts of the interposer. Variations in thickness and/or warping of any of the substrates supporting the opposing electrical contact arrays and the interposer may also cause difficulty establishing reliable contact. Many interconnect devices use elastomeric electrical contacts that are compressed between the electrical contacts of the opposing electrical component arrays such that the elastomeric electrical contacts apply a mechanical force to the electrical contacts to facilitate establishing and maintaining reliable electrical contact between the opposing electrical component arrays. Compression of the elastomeric electrical contacts also allows for some degree of nonplanarity between, and/or misalignment of, the electrical contacts of the opposing electrical component arrays that may be caused by the warping, variations of height, and/or variations of thickness described above.
Elastomeric electrical contacts typically include an elastomeric body and electrically conducting pathway. Some known elastomeric electrical contacts, sometimes referred to as “filled elastomers”, include an elastomeric body having an interior that is filled with one or more electrically conducting materials. However, filled elastomers may have a limited elastic working range because of the amount of conducting filler needed to reach the percolation threshold and conduct a predetermined amount of electrical current, which may increase contact forces above desired levels. Other known elastomeric electrical contacts include an elastomeric body that includes an electrically conductive pathway formed on an exterior of the elastomeric body. Elastomeric electrical contacts having an electrically conductive pathway on an exterior thereof may have a higher elastic working range than filled elastomeric electrical contacts. However, the electrically conductive pathway may have a lower current carrying capability than filled elastomeric electrical contacts. For example, the dimensions of the electrically conductive pathway may be limited by the desired elastic working range of the elastomeric body. Specifically, if the electrically conductive pathway is formed too large, it may limit the elastic working range of the elastomeric body or the electrically conductive pathway. However, if the conductive pathway is formed too small, it may not carry a desired level of electrical current. Moreover, if formed too small, the conductive pathway may crack and/or fracture during compression of the elastomeric body such that the electrical circuit is broken.
What is needed therefore is an elastomeric electrical contact that has a higher current carrying capability than known elastomeric electrical contacts having exterior electrically conductive pathways while maintaining a predetermined elastic working range without cracking and/or fracture of the pathway.